05000382/LER-2009-004, Regarding Condition Prohibited by Technical Specification with Log Power Channel Inoperable
| ML093480490 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 12/11/2009 |
| From: | Murillo R Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| W3F1-2009-0072 LER 09-004-00 | |
| Download: ML093480490 (9) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 3822009004R00 - NRC Website | |
text
Entergy Entergy Operations, Inc.
17265 River Road Killona, LA 70057-3093 Tel 504-739-6715 Fax 504-739-6698 rmurill@entergy.com Robert J. Murillo Licensing Manager Waterford 3 W3F1-2009-0072 December 11, 2009 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001
Subject:
Licensee Event Report 09-004-00 Waterford Steam Electric Station, Unit 3 (Waterford 3)
Docket No. 50-382 License No. NPF-38
Dear Sir or Madam:
Entergy is hereby submitting Licensee Event Report (LER) 09-004-00 for Waterford Steam Electric Station Unit 3. This report provides details for a condition prohibited by Technical Specification. During Reactor Protection System (RPS) maintenance on the Log Power channel, the RCS Flow Low trip channel was not considered inoperable and placed in trip or bypass condition within one hour. The Log Power signal provides automatic removal of the operating bypass, when utilized, for RCS Flow Low.
This report contains no new commitments. Please contact Robert J. Murillo at (504) 739-6715 if you have questions regarding this information.
7S-e-rely, SjC/4V RJM/JDW
Attachment:
Licensee Event Report 09-004-00
-- le §a
W3F1-2009-0072 Page 2 (w/Attachment) cc:
Mr. Elmo E. Collins, Jr.
Regional Administrator U. S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 NRC Senior Resident Inspector Waterford Steam Electric Station Unit 3 P.O. Box 822 Killona, LA 70066-0751 U. S. Nuclear Regulatory Commission Attn: Mr. N. Kalyanam Mail Stop O-07D1 Washington, DC 20555-0001 Wise, Carter, Child & Caraway ATTN: J. Smith P.O. Box 651 Jackson, MS 39205 Winston & Strawn ATTN: N.S. Reynolds 1700 K Street, NW Washington, DC 20006-3817 Morgan, Lewis & Bockius LLP ATTN: T.C. Poindexter 1111 Pennsylvania Avenue, NW Washington, DC 20004 Louisiana Department of Environmental Quality Office of Environmental Compliance Surveillance Division P. 0. Box 4312 Baton Rouge, LA 70821-4312 R.K. West, lerevents@inpo.org - INPO Records Center
W3F1-2009-0072 Page 3 e-mail:
(w/Attachment)
J.A. Kowalewski C.F. Arnone K. Christian K.D. Nichols K.S. Cook J.F. McCann B. Ford B.R. Lanka M. Schaible D.R. Morris R.J. Murillo S.L. Anders W.E. McKinney J.A. Ridgel B.A. Lindsey C. Fugate R.G. Putnam C.L. Alday J.J. Lewis A.B: Pilutti J.L. Hornsby (W-GSB-300)
(W-MSB4-300)
(W-GSB-318)
(W-GSB-315)
(W-MSB4-336)
(K-WPO-12C)
(M-ECH-42)
(W-GSB-315)
(W-EEC-650)
(W-GSB-350)
(W-GSB-318)
(W-ADM-500)
(W-GSB-102)
(W-GSB-260)
(W-MSB4-325)
(W-MSB4-217)
(W-MSB4-220)
(W-GSB-201)
(W-GSB-365)
(W-MSB4-244)
(W-MSB4-238)
(W-GSB-1 00)
(w/Attachment) bcc:
Waterford 3 Records Center
Attachment W3F1-2009-0072 Licensee Event Report 2009-004-00
NRC FORM 366 U.S. NUCLEAR REGULATORY APPROVED BY OMB NO. 3150-0104 EXPIRES 8/31/2010 COMMISSION (9-2007)
Estimated burden per response to comply with this mandatory information collection request:
80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the Records Management Branch LICE SEE VEN REP RT (ER)
(T-6 E6), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-LICENSEE EVENT REPORT (LER)a Sguc vantoheDs e
e n
anadR mail to bjsl@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202 (3150-0104), Office of Management and Budget, WashingtonDC 20503. If a means used to impose information collection does not display a currently valid 0MB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the (Serees information collection.
(Seereverse for required number of digits/characters for each block) informationcollection.
1
- 3. PAGE Waterford 3 Steam Electric Station 05000382J 1 OF 5
- 4. TITLE Condition prohibited by Technical Specification with Log Power Channel Inoperable
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SN)VFACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SEQUENTIAL I REV MONTH DAY YEAR NA 05000 NUMBER NO NA 05000 FACII7T0 NAME' DOCKET NUMBER 07 05 2009 2009 - 004 -
00 12 11 2009 NA 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
El 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii) 1E 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
E] 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
__ 20.2203(a)(2)(i)
[E 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
[E 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL E] 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
I] 73.71(a)(4) 1E00 l 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71 (a)(5)
El 20.2203(a)(2)(v)
[-]
50.73(a)(2)(i)(A)
[1 50.73(a)(2)(v)(C)
E OTHER Voluntary Report Specify in Abstract below or in El 20.2203(a)(2)(vi)
Z 50.73(a)(2)(i)(B)
El 50.73(a)(2)(v)(D)
BACKGROUND The Reactor Protective System (RPS) portion of the Plant Protection System (PPS) [JC] consists of sensors, calculators, logic, and other equipment necessary to monitor selected Nuclear Steam Supply System (NSSS) and containment conditions and to effect reliable and rapid Control Element Assembly (CEA) insertion (reactor trip) if any or a combination of the monitored conditions approach specified safety system settings.
The system's functions are to protect the core and Reactor Coolant System (RCS) [AB] pressure boundary for defined anticipated operational occurrences (AOOs) and also to provide assistance in limiting the consequences for certain postulated accidents. Manual reactor trip is also provided.
Some reactor trip signals are provided with operating bypasses that are required to allow reactor startup.
The High Logarithmic Power (HLP), High Local Power Density (LPD), Low Departure from Nucleate Boiling Ratio (DNBR), and Low RCS Flow trips are allowed to be bypassed at prescribed Modes or power levels since these trips would otherwise generate an unnecessary trip signal during reactor startup and power increase. The LPD, DNBR, and RCS Flow Low operating bypasses are required to be automatically removed by the respective channel Log Power excore nuclear instrumentation (ENI) [IG] signal at 1 E-4%
power (increasing) to ensure the channel function is available to trip the reactor.
Technical Specification (TS) 3.3.1 requires a minimum of 3 out of the 4 Log Power trip channels to be OPERABLE when Log Power is below 1 E-4% power in Mode 2, and also in Modes 3, 4 and 5 when CEAs are capable of withdrawal. However, the TS does not require the Log Power trip channels to be OPERABLE while in Mode 1 or above 1 E-4% power, even though the DNBR, LPD, and RCS Flow Low trip channels with Log Power dependent operating bypasses are required to be OPERABLE in Modes 1 and 2.
TS 3.3.1, Table 3.3-1 note C requires the PPS operating bypasses for LPD, DNBR, and RCS Flow Low be automatically removed when at or abovel E-4% power. This automatic function is dependent upon the Log Power output signal and associated 1E-4% power bistables on the same PPS train. When the Log Power ENI is rendered inoperable, TS Table 3.3-1 note C is not met verbatim for LPD, DNBR, and RCS Flow Low on the same train, even though these operating bypasses are manually defeated by key switch, with their keys removed.
With one or two DNBR, LPD and/or RCS Flow trip channels inoperable, TS 3.3.1 Table 3.3-1 ACTIONs require the inoperable channel(s) to be placed in the bypassed or tripped condition within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
EVENT DESCRIPTION
On 8/20/09, the NRC Resident inspector challenged the Waterford 3 application of the TS 3.3.1 associated with the PPS operating bypasses when the Log Power channel (B) was considered inoperable while in Mode
- 1. At the time, PPS Log Power channel B was considered inoperable; however, DNBR, LPD, and RCS Flow Low were not considered inoperable based on the understanding that PPS Log Power channels were not required in Mode 1 and there was no reliance on Log Power channels for the automatic removal of operating bypasses since these operating bypasses were not being utilized and were secured in the unbypass position with keys removed from the keyswitches. In response, Waterford 3 applied literal TS 3.3.1 Table 3.3-1 note C wording, which required these operating bypasses to be "automatically removed", declared DNBR, LPD, and RCS Flow Low trip channels inoperable, entered TS 3.3.1 ACTION 2, and placed these trip channels in bypass.
Historical applications of TS 3.3.1 were the following:
The channel B PPS Log Power ENI had been declared inoperable 9/1/2008 since the previous reactor startup, due to elevated power indication at very low power levels due to external induced noise while significantly below power levels typical for approaching reactor criticality. Further evaluation resulted in determination that the Log Power channel B had been Operable, but degraded, fully capable of performing the function to automatically remove the operating bypasses of LPD, DNBR, RCS Flow and Log Power PPS channels.- The TS 3.3.1 ACTION 2 was exited, and the trip channels were restored.
On 10/15/09, while performing reviews of plant procedures and historical log entries, Waterford 3 plant personnel discovered Technical Specification (TS) 3.3.1 requirements of Table 3.3-1, note C, were not met during past maintenance testing. Specifically, on 7/5/09, during PPS channel C Log Power calibration test, DNBR and LPD trip channels on the associated channel being tested (C) were bypassed, however, the RCS Flow Low trip channel was not placed in bypass or in tripped condition,, or otherwise declared inoperable.
On 11/28/07, during the channel (C) calibration test while D channel ENI Log Power was concurrently inoperable, DNBR and LPD trip channels on the associated channel being tested (C) were bypassed. LPD and DNBR was placed in the tripped condition on the associated channel already inoperable (D). However, RCS Flow Low trip channels were not placed in bypass or in tripped condition, or otherwise declared inoperable on either train (C or D). The Operations procedure for Plant Protection System provides requirements for testing Excore/CPC channel while another channel is already inoperable; however, this procedure does-not address the RCS Flow Low trip channel.
Compliance was not met for TS 3.3.1 Table 3.3-1 Action 2, Action 3, nor TS 3.0.3.
CAUSAL FACTORS NRC issuance of Amendment No. 40 (ADAMS Accession No. ML021760266) changed the Technical Specifications by removing the operability and surveillance requirements for Log Power Channels when reactor power is above 1E-4% of rated thermal power. The NRC Safety Evaluation Report explicitly stated that the operation of the Log Power Level Channels at power levels above 1 E-4% of rated thermal power (RTP) is recognized to be inappropriate for technical specification requirements since on startup, the trips are bypassed. This led to the philosophy that above 1 E-4% RTP with the DNBR, LPD, and RCS Flow trips enabled and able to perform their specified safety functions that a log power issue did not affect DNBR, LPD, and RCS Flow trip operability. The 1 E-4% bistable which is actuated by log power has no adverse impact on DNBR, LPD, and RCS Flow trips above 1 E-4% once the trips are enabled.
NRC issuance of Amendment No. 145 (ADAMS Accession No. ML0217904720) was intended to clarify the known TS Table 2.2-1 and 3.3-1 verbatim compliance issues associated with TS Table 3.3-1 log power. This change clarified the 1 E-4% power level is associated with neutron power and not thermal power. This amendment did not change the NRC Amendment No. 40 philosophy.
The Maintenance Instrumentation procedures for Log Power testing and maintenance address the need to consider bypassing LPD and DNBR trip channel; however, the procedures do not specifically address the need to consider RCS Flow Low trip channel operability. The DNBR and LPD were included, not because their operability were believed to be affected, but as a conservative action because of the integrated circuitry could potentially cause an unnecessary DNBR and LPD bistable trip while performing test or maintenance activities on the associated Log Power channel. This requirement in TS Table 3.3-1 note C for operating bypasses to be automatically removed had been interpreted as being satisfied, not requiring the Log Power channel, when these operating bypasses are removed and disabled by their key switches removed.
CORRECTIVE ACTIONS
Operations Standing Order was put in place 8/31/09 to ensure that LPD, DNBR, and RCS Flow is bypassed or placed in trip condition when the associated Log Power channel is rendered inoperable in Modes 1 and 2, regardless if Log Power trip channel is required or if the operating bypasses are utilized.
A TS amendment request was submitted to NRC via Entergy Letter No. W3F1-2009-0045 (ADAMS Accession No. ML092990199) to clarify the TS related requirement of operating bypass to read, "shall be capable of automatic removal whenever the operating bypass is enabled and logarithmic power is above the 1 E-4% bistable setpoint."
Changes to the maintenance procedures for Log Power are being finalized to address bypassing or placing RCS Flow Low in trip condition to ensure compliance with TS when the associated Log Power channel is rendered inoperable due to maintenance testing.
Changes to the PPS Operations procedure are being made to address bypassing or placing RCS Flow Low in trip condition to ensure compliance with TS when the associated Log Power channel is rendered inoperable due to maintenance testing while a second Log Power channel is already inoperable.
.SAFETY SIGNIFICANCE Four PPS measurement channels with electrical and physical separation are provided for each parameter used in the direct generation of trip signals. A two-out-of-four coincidence of like trip signals is required to generate a reactor trip signal. The fourth channel is provided as an installed spare and allows bypassing of one channel while maintaining a two-out-of-three logic protection system. In these cases, where RCS Flow channel was not bypassed or placed in trip condition, the operating bypasses were not utilized, but maintained locked in the un-bypassed condition with key removed, such that the trip function was not affected by the associated log power channel being inoperable. Accordingly, there were no safety consequences associated with this condition.
SIMILAR EVENTS
A review of previous events was performed to identify similar licensee events at Waterford 3 reported in the last three years. There were no similar licensee events identified.
ADDITIONAL INFORMATION
Energy industry identification system (EIIS) codes are identified in the text within brackets [].